Part of the issue is that the free VSS writer provided by Microsoft isn't as capable as the writers provided by the SAN vendors. I'll have to go back and refresh myself a little more to give you the specifics of the limitations there, but the end result was that if you have a small store (<20GB), you can do online backups to disk in a reasonable period of time and use those more effectively than snapshots in a lot of cases. You can even run pretty frequent incremental or differential backups using the traditional tools and not need to go to VSS at all.
Windows VSS writer snapshots can't be used in a redirected restore or recovery storage group for example. -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Matthew Joyce Sent: Friday, June 25, 2004 1:07 AM To: Exchange Discussions Subject: RE: Shadow Copying of Exchange 2003 An interesting post to what was a deteriorating thread. I'm interested to know what size store you had in mind for your scenario. If I only have a small store, copies will be fast and drive space is cheap, does this make it an attractive solution for small installations ? thanks Matt Joyce Children's Cancer Institute Australia http://www.ccia.org.au > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On > Behalf Of Webb, Andy > Sent: Friday, 25 June 2004 11:32 AM > To: Exchange Discussions > Subject: RE: Shadow Copying of Exchange 2003 > > > One of many other differences with Exchange and SQL is that > because of the structure of the files, much larger portions > of the data may change between snapshots. > > So, you snap at 9pm, then do a backup, which zeros out > deleted pages, then maintenance runs to clean out tombstoned > indexes, coallesce pages and about 8 other things, then you > snap again at 9am. > > At 10am your store crashes and so you pull back the 9am > snapshot - it's pretty quick, but still not instant because > between 9am and 10am 80% of your users were online > regenerating new indexes and making changes to all the items > they received overnight. But all and all you have somewhere > south of 5% of the blocks to copy from the snapshot back onto > the production database LUNs. But wait - it's not really > wise to lose your "latest state", so somehow before you snap > back to 9am, you should get a backup of the store at the time > of the crash. This isn't a snapshot at this point. > > But let's assume you have a way to handle that responsible > backup. You snap back to 9am and discover that that store is > corrupt too. Bummer. Now you have to snap back to 9pm and > somewhere north of 40% of your database pages have changed. > Bummer again, that's going to take actual time to copy that > much data. So, now it's 3pm or so and you're finishing up > the copy and you have to get the store started and replay any > logs you have so you don't lose all that data from the > 9pm-10am timeframe. That might be a lot of logs, so again, > not instant. > > Every one of these challenges can be addressed with money and > hardware. > > For some people, the cost of having the mail system down is > commensurate with those costs. For others it's not; a more > traditional tape based system or "online backup" scenario is > more practical. > > Regardless, this illustrates that snapshot backups are an > iceberg and the VSS capability in the OS is merely the tip. > > There were some good presentations at TechEd on this and > there are a couple new whitepapers out on the Exchange Site. > > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On > Behalf Of Henry Sieff > Sent: Thursday, June 24, 2004 5:00 PM > To: Exchange Discussions > Subject: RE: Shadow Copying of Exchange 2003 > > Volume shadow copy is like the various volume copying > products used for years now on high end SAN's (like HDS > truecopy/shadowcopy). Basically, you have two equal sized > volumes (PRODUCTION and BACKUP). These are kept in sync by > the SAN controller. At any time, you can break the sync, and > then BACKUP is a valid backup of PRODUCTION. You can mount > BACKUP on another server (or the same one if you're not > running MSCS) and use the file on it or whatever. > > All the syncing is block level, and even if you've had it > unsynced for a while, its pretty quick to catch up once you > unmount and resync. > > Hence the issue (up until now?) with exchange/SQL. While exchange (or > SQL) > is running, the files themselves are inconsistant, so what > you had to do was stop exchange/SQL, then break the pair, > then you restart exchange SQL. Then you could make a tape > copy of the BACKUP volume at your leisure, or not. > > What Volume Shadow Services is supposed to do is handle all > of that by making the files consistant and then syncing then > breaking, in effect giving you an instantaneous backup. > > Henry > > > -----Original Message----- > > From: [EMAIL PROTECTED] > > [mailto:[EMAIL PROTECTED] > Behalf Of Ajay > > Kulsh > > Sent: Thursday, June 24, 2004 2:32 PM > > To: Exchange Discussions > > Subject: Re: Shadow Copying of Exchange 2003 > > > > > > Ken, > > > > I get the error message "Sorry this meeting has already finished". > > -- > > > > And, about one of my original questions, how can the huge > > exchange database > > of many GBs be copied in "about a minute" and where it is > written to? > > > > So far, only Samantha's response makes sense unless one of > > you have actually > > used this feature and can give some inside info. > > > > Jay > > > > ----- Original Message ----- > > From: Ken Cornetet > > To: Exchange Discussions > > Sent: Thursday, June 24, 2004 8:31 AM > > Subject: RE: Shadow Copying of Exchange 2003 > > > > > > You all may want to view this webcast: > > > > Go to: http://www.placeware.com/cc/mseventsbmo/join > > Your Name: (enter your name) > > Meeting ID: 1032251381 > > Meeting Password: webcast > > > > -----Original Message----- > > From: [EMAIL PROTECTED] > > [mailto:[EMAIL PROTECTED] On Behalf Of > > Bridges, Samantha > > Sent: Thursday, June 24, 2004 9:57 AM > > To: Exchange Discussions > > Subject: RE: Shadow Copying of Exchange 2003 > > > > > > I understand that you cannot or should not think of Shadow > copying the > > Exchange IS. The shadow copying feature in Windows 2003 is > for the OS > > not for a database. To be clearer, you can use shadow copy for > > Windows or the OS not for the Exchange database. > > > > Hope this makes sense. We were in the same thought pattern > as you and > > learned this wasn't going to work. > > > > Samantha > > > > -----Original Message----- > > From: Ajay Kulsh [mailto:[EMAIL PROTECTED] > > Sent: Wednesday, June 23, 2004 8:42 PM > > To: Exchange Discussions > > Subject: Shadow Copying of Exchange 2003 > > > > > > I need some enlightenment regarding Shadow Copying of Exchange 2003. > > > > I have read MS article - 822896 and some other references to > > understand > > shadow copying. What is not clear to me that if it takes > > typically only > > *about a minute* to create a shadow copy, how long does it > > normally take > > to write this data to a backup hardware? And while backup program is > > writing this, where is data kept? Memory cannot keep so much > > and I don't > > see any hard drive space requirements mentioned. > > > > Can shadow copying of Exchange 2003 only work with backup > > like SAN, not > > normal tape drive? > > > > Jay Kulsh > > > > > > _________________________________________________________________ > > List posting FAQ: http://www.swinc.com/resource/exch_faq.htm > > Web Interface: > > http://intm-dl.sparklist.com/cgi-bin/lyris.pl?enter=exchange&t > > ext_mode=& > > lang=english > > To unsubscribe send a blank email to > > %%email.unsub%% > > Exchange List admin: [EMAIL PROTECTED] > > To unsubscribe via postal mail, please contact us at: > > Jupitermedia Corp. > > Attn: Discussion List Management > > 475 Park Avenue South > > New York, NY 10016 > > > > Please include the email address which you have been contacted with. > > > > --- > > [This E-mail scanned for viruses by Declude Virus] > > > > --- > > [This E-mail scanned for viruses by Declude Virus] > > > > > > _________________________________________________________________ > > List posting FAQ: http://www.swinc.com/resource/exch_faq.htm > > Web Interface: > > http://intm-dl.sparklist.com/cgi-bin/lyris.pl?enter=exchange&t > ext_mode=& > lang=english > To unsubscribe send a blank email to > %%email.unsub%% > Exchange List admin: [EMAIL PROTECTED] > To unsubscribe via postal mail, please contact us at: > Jupitermedia Corp. > Attn: Discussion List Management > 475 Park Avenue South > New York, NY 10016 > > Please include the email address which you have been contacted with. > > > > _________________________________________________________________ > List posting FAQ: http://www.swinc.com/resource/exch_faq.htm > Web Interface: > http://intm-dl.sparklist.com/cgi-bin/lyris.pl?enter=exchange&t > ext_mode=& > lang > =english > To unsubscribe send a blank email to > %%email.unsub%% > Exchange List admin: [EMAIL PROTECTED] > To unsubscribe via postal mail, please contact us at: > Jupitermedia Corp. > Attn: Discussion List Management > 475 Park Avenue South > New York, NY 10016 > > Please include the email address which you have been contacted with. > > > _________________________________________________________________ > List posting FAQ: http://www.swinc.com/resource/exch_faq.htm > Web Interface: > http://intm-dl.sparklist.com/cgi-bin/lyris.pl?enter=exchange&t ext_mode=& lang =english To unsubscribe send a blank email to %%email.unsub%% Exchange List admin: [EMAIL PROTECTED] To unsubscribe via postal mail, please contact us at: Jupitermedia Corp. 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